BOSTON — The Red Sox got a glimpse of a promising part of their future on Wednesday night. But their disappointing present continued to follow them.

On a night rookie starter Brayan Bello delivered a sparkling start, frustration continued to carry the Red Sox further out of the wild-card race. George Springer delivered an RBI double in the 10th inning, which was the difference as the Red Sox lost another series to an American League East opponent with a 3-2 loss to the Blue Jays.

Bello gave the Red Sox a chance over five innings, but the Red Sox’s offense failed to deliver. They wasted a pair of bases-loaded opportunities in the late innings, which paved the way for extras, where Springer smacked Ryan Brasier’s first pitch off the left-field wall, giving the Jays the lead for good.

The Red Sox, despite the automatic runner on second, couldn’t tie the game as Alex Verdugo flew out, J.D. Martinez grounded out, and after Rafael Devers was intentionally walked, Kiké Hernandez struck out to end the game.

The Red Sox dropped to 3-12 against the Blue Jays this season, and have now lost all five series against them.

Though it didn’t end the way he wanted, Bello walked away with easily the best start of his young career, a step in the right direction after experiencing growing pains and tough luck in his first handful of outings.

The rookie – who entered with an 8.47 ERA through his first five outings (four starts) returned from a three-week spell on the injured list and breezed through a dangerous Blue Jays lineup the first time through the order. He needed just 26 pitches to do so as his 96 mph sinker continued to play and ground balls, which have gone for cheap hits in past starts, finally started going his way, which included a well-executed 6-4-3 double play started by Bobby Dalbec to end the second inning.

Bello, who pitched a no-hitter for the Sea Dogs this season, started getting into trouble the second time through the Jays’ lineup as he nursed a 2-0 Red Sox lead on Franchy Cordero’s early home run.

Springer led off the fourth with a single before Vladimir Guerrero Jr. drew a walk, which led to a mound visit from Red Sox pitching coach Dave Bush. Two batters later, Alejandro Kirk hit an RBI single to cut the Red Sox’s lead in half.

But Bello found a way to limit the damage. After throwing just one change-up over his first three innings, he went to it heavily to finish his outing. It paid off. He struck out Teoscar Hernandez with two change-ups before repeating the approach to Bo Bichette, who struck out after missing two change-ups.

Bello continued the change-up-heavy attack in the fifth, when he struck out Matt Chapman swinging at a 98 mph four-seamer that was set up by the change-up. After Whit Merrifield singled, Bello then struck out Jackie Bradley Jr. with a dose of change-ups.

But with two outs, Bello couldn’t protect the lead as he entered a third time through the order. Springer singled before Guerrero Jr.’s RBI single to right tied the game. Still, Bello limited the damage, as he forced Lourdes Gurriel Jr. into an inning-ending fly out to center.

Bello went five innings – the longest of his big-league career – and struck out a career-high seven batters. He induced 13 swings and misses, including seven with the change-up.

He and the bullpen gave the Red Sox a chance. Matt Barnes pitched a scoreless sixth and Garrett Whitlock threw a shutout seventh on just six pitches before the Sox had their biggest chance of the night. With two outs, Bobby Dalbec drew a walk, Reese McGuire singled and Jarren Duran reached when Guerrero Jr. mishandled a ball at first to load the bases. But they went away empty-handed after Rob Refsnyder’s fly out to center.

The Red Sox squandered another big chance after Whitlock’s shutdown eighth, as Verdugo singled and Devers doubled to put two runners in scoring position with one out, which forced the Jays to summon right-hander Anthony Bass. But Hernández struck out swinging after missing on three sliders before Cordero was intentionally walked to load the bases and give Bass a righty-on-righty matchup with Dalbec. It went poorly for Dalbec, who struck on three pitches to end the rally.